In firing a missile, whether for test or in combat, it is important that the gun crew be given a signal indicating that all safety measures have been taken and that the missile is operative before it is fired. With a tandem or multiple charge warhead, a crush switch or other means provides a signal indicating that the missile has reached a predetermined position with respect to the target. A first charge, usually some type of shaped tip charge to defeat reactive armor, and other charges are detonated in timed sequence. The interval between detonations is usually less than two milliseconds and less than one microsecond accuracy is required. In addition, the timing of detonations should be adjustable.
In testing such a missile it is important to know the timing of the detonation signals as it may have to be adjusted in order to obtain best results.